Paper feeder apparatus and facsimile apparatus

ABSTRACT

A paper feeding apparatus is provided with a pressing arm that presses the separator to a paper feed roller, a document guide that has a pair of guide parts for pressing a document to the paper feed roller, and a spring part that applies spring force to the pressing arm and the document guide. The guide parts are located at both edges of the separator. The document guide guides the document so that the front edge of the document passes over the paper feed roller, and presses the document to the paper feed roller.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a paper feeder apparatus and afacsimile apparatus or similar printing apparatus having the paperfeeder apparatus.

[0003] 2. Description of the Related Art

[0004] Conventionally, as shown in FIG. 5, a paper feeder used in afacsimile apparatus comprises a lower document guide 1 for settingdocuments, which is concurrently a paper holder, an upper document guide2 positioned above the lower document guide 1, a paper feed roller 3,and a separator 4 for preventing double feeding of documents cooperateswith the paper feed roller 3. A pressing part 5 is mounted to the upperdocument guide 2 at the support point O and presses the separator 4towards the paper feed roller 3, and a spring member 6 such as acompression spring presses the edge of the pressing part so that thepressing part 5 presses the separator 4. A document guide panel 7 thatincludes a pair of leaf springs at both edges of the separator 4 forguiding the front edge of a document to the paper feed roller 3 and forpressing the document to the paper feed roller 3 is also provided.

[0005] When documents are set in the documents holder, the documentsguide panel 7 pushes the documents gently towards the paper feed roller3. Then the paper feed roller 3 rotates to send the document between thepaper feed roller 3 and the separator 4, preventing double feeding ofdocuments by the paper feed roller 3 and the separator 4. Thus, thedocument is transferred to a scanner section positioned downstream ofthe paper feeder.

[0006] In the conventional paper feeder, a pair of leaf springs is usedas document guide panel 7 for guiding the front edge of a document andfor pressing the document to the paper feed roller gently. However,pressing power applied to a document by the pair of leaf springs isdesigned to be very small (for example, about 10 to 20 g). As a result,the leaf springs are small and easily deformable, hence great attentionis necessary for handling and installing them. Further, because theconventional document guide 7 uses the spring power of the leaf springsfor pressing a document to the paper feed roller, high accuracyproduction (accuracy in size and spring constant) is necessary to avoidirregularity or variation of the pressing power. As a result,significant manufacturing and assembly costs cannot be avoided.

SUMMARY OF THE INVENTION

[0007] Accordingly, it is an objective of the present invention toprovide a paper feeder apparatus at low cost, using a part withoutspring operation, instead of a pair of leaf springs, for guiding thefront edge of the document and for pressing the document to a paper feedroller.

[0008] Another objective of the present invention is to provide a paperfeeder apparatus that can reduce the number of parts and make partsproduction easy.

[0009] The present invention provides a paper feeder apparatus includinga paper feed roller that feeds a document, a separator that preventsdouble feeding of documents by said paper feed roller, and a pressingarm that presses the separator to the paper feed roller. A documentguide is provided with a pair of guide parts, the guide parts beinglocated at both edges of the separator, the guide parts guiding thedocument so that a front edge of the document passes over the paper feedroller, and the guide parts pressing the document to the paper feedroller. A spring part provides a spring force to the pressing arm and tothe document guide so that the pressing arm presses the separator andthe document guide presses the document towards the paper feed roller.

[0010] In this configuration, two leaf springs used conventionally arenot necessary and instead, only the document guide of one piececonstructions without a spring is used.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The present invention is further described in the detaileddescription which follows, in reference to the noted plurality ofdrawings by way of non-limiting examples of exemplary embodiments of thepresent invention, in which like reference numerals represent similarparts throughout the several views of the drawings, and wherein:

[0012]FIG. 1 illustrates a schematic cross-sectional view of a paperfeeder according to an embodiment of the present invention;

[0013]FIG. 2 illustrates a schematic perspective view of a facsimileapparatus comprising a paper feeder shown in FIG. 1;

[0014]FIG. 3 illustrates a schematic perspective view of the main partof the paper feeder shown in FIG. 1;

[0015] FIGS. 4(a), 4(b), and 4(c) illustrate in schematic crosssectional views, spring force control operation by means of spring forcecontrol used in the paper feeder according to the present invention; and

[0016]FIG. 5 illustrates a schematic cross sectional view of aconventional paper feeder.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] This invention will be described in further detail by way ofexample with reference to the accompanying drawings.

[0018]FIG. 1 is a schematic cross-sectional view of the paper feeder ofthe embodiment of the present invention. FIG. 2 is a schematicperspective view of the facsimile apparatus that is provided with thepaper feeder. FIG. 3 shows a schematic perspective view of the mainportion of the paper feeder shown in FIG. 1. FIGS. 4(a), 4(b), and 4(c)show schematic cross-sectional views for describing the spring forcecontrol operation by means of spring force control that the paper feederuses.

[0019] The facsimile apparatus, indicated by reference number 9 as awhole in FIG. 2, has a document holder 11 at the rear portion of theapparatus and a paper feeder shown in FIG. 1 at the lower portion of theapparatus.

[0020] In FIG. 1 and FIG. 3, the paper feeder 10 comprises a lowerdocument guide that is concurrently a document holder, an upper documentguide 12 installed above the lower document guide 11, a paper feedroller 13, and a separator 14 that advances or forwards a document whilepreventing double feeding in cooperation with the paper feed roller. Apressing arm 15 has a pressing portion 15 a to press the separator tothe paper roller 13 and a spring part 16 supplies spring force to thepressing arm 15 so that the pressing arm 15 presses the separator 14. Adocument guide 17 is located at both sides of the separator 14, andguides the document so that the front edge of the document passes overthe paper feed roller 13. A pair of guide parts 17 a press the documentto the paper feed roller 13.

[0021] In contrast to the conventional two leaf springs structure, thedocument guide 17 is made of resin, formed unitarily and of one piececonstruction, and is equipped with a support axis 17 b at the edgespaced from the guide parts 17 a that guide a document and press thedocument to the feed roller 13. The support axis 17 b is positioned atthe first support point P spaced from the first pressing point A atwhich the guide parts 17 a press the document to the paper feed roller13. The document guide 17 is installed at the upper document guide 12 sothat it can rotate freely.

[0022] In this configuration, the document guide 17 can move about thefirst support point P. Pressed downward by the spring part 16, the pairof guide parts 17 a can be pressed to the paper feed roller 13. Thus itis possible to perform the same function as that of conventionaldocument guide panel 7 (FIG. 5) that uses a pair of leaf springs.Production of the document guide 17, that is made of resin in one pieceis easier in comparison with that which requires leaf springs; hence itis possible to realize cost savings.

[0023] The pressing arm 15 has a support axis 15 b spaced from thepressing portion 15 a and the support axis 15 b is at the second supportpoint Q located between the second pressing point B, at which the pressmember 15 presses the separator 14, and the first support point P. Thepressing arm 15 is installed at the upper document guide 12 so that itcan rotate freely.

[0024] Thus, the pressing arm 15 can pivot at the second support pointQ. Further, the pressing arm 15 stretches upward through the largeopening of the document guide 17, and in the opposite direction to theother side of the support axis 15 b. The pressing arm 15 has a springconnection section 15 c facing the document guide 17 at the end thereof.

[0025] A spring force controlling section 20 for controlling a springforce of a spring part 16 is located at the position of the documentguide 17 facing towards the spring connection section 15 c of thepressing arm 15. As shown in FIG. 4, the spring force controllingsection 20 includes a spring support 22 moveably provided within thegroove 21 formed in the document guide 17. The spring support 22 hasthree spring support faces 22 a, 22 b and 22 c which are of differentheights. The spring part 16 is set on one of the spring support faces 22a, 22 b and 22 c at the bottom end and is connected to the springconnection section 15 c of the pressing arm 15 at the upper end. Thus,the spring part 16 pushes down the document guide 17 at the bottom endso that the pair of guide parts 17 a of the document guide 17 pressesagainst the paper feed roller 13. At the same time, the spring part 16pushes up the pressing arm 15 at the top, therefore, the pressingportion 15 a of the pressing arm 15 can press the separator 14.

[0026] As shown in FIGS. 4(a), 4(b) and 4(c), the spring support faces22 a, 22 b and 22 c that support the bottom of the spring part 16 can beswitched by moving the spring support 22. Thus, the spring force of thespring part 16 can be changed, as a result, the pressure force exertedby the pressing portion 15 and the document guide 17 can be controlled.

[0027] In FIG. 1 and FIG. 3, it is necessary to set the pressure forcewith which the document guide 17 presses the document to the paper feedroller 13 (the pressure force at the first pressing point A) to besmall, and to set the pressure force of the pressing arm 15 that pressesthe separator 14 to the paper feed roller 13 (the pressure force at thesecond pressing point) to be large. In order to accomplish this with thecommon spring part 16, the spring force of the spring part 16 needs toprovide the pressure force required by the pressing portion 15. Inaddition, the position, at which the spring part 16 presses the documentguide 17, is located near the first support point P.

[0028] In this configuration, the distance from the first support pointP to the spring part 16 can be quite smaller than that from the firstsupport point P to the first pressing point A; hence the pressure forceapplied to the document at the document guide 17 can be very small. Bysetting the ratio of these distances appropriately, the pressure forceapplied to documents on the document guide 17 can be made to have asmall value.

[0029] In the above-mentioned paper feeder apparatus, when plural pagesof documents are put on the document holder 11, the front edge of thedocument is guided by the pair of guide parts 17 a of the document guide17. The document passes between the paper feed roller 13 and the guideparts 17 a, and is inserted to the contact section of the paper feedroller 13 and the separator 14. The pair of guide parts 17 a of thedocument guide 17 gently press the document to the paper feed roller 13slightly upstream of the contact point of the paper feed roller 13 andthe separator 14. When the paper feed roller 13 rotates in thissituation, the document, gently pressed to the paper feed roller 13, isinserted between the paper feed roller 13 and the separator 14 by thepaper feed roller 13. The document is thus transferred downstream,preventing double feeding by the paper feed roller 13 and the separator14. Thus, it is possible to ensure that documents are separated and arefed in a page-by-page fashion.

[0030] As mentioned above, the paper feeder apparatus of the presentinvention comprises the document guide 17 of one piece structure thathas the pair of guide parts 17 a located at both sides of a separator.By applying the spring force of the spring part 16 to the document guide17, the pair of guide parts 17 a presses the document to the paper feedroller 13. This makes it possible to feed documents by guiding the frontedge of the document and pressing the document to the paper feed

[0031] It is noted that the foregoing has been provided merely for thepurpose of explanation and is in no way to be construed as limiting ofthe present invention. While the present invention has been describedwith reference to an exemplary embodiment, it is understood that thewords which have been used herein are words of description andillustration, rather than words of limitation. Changes may be made,within the purview of the appended claims, as presently stated and asamended, without departing from the scope and spirit of the presentinvention in its aspects. Although the present invention has beendescribed herein with reference to particular means, materials andembodiments, the present invention is not intended to be limited to theparticulars disclosed herein; rather, the present invention extends toall functionally equivalent structures, methods and uses, such as arewithin the scope of the appended claims.

[0032] This application is based on the Japanese Patent Application No.2000-299769 filed on Sep. 29, 2000, entire content of which is expresslyincorporated by reference herein.

What is claimed is:
 1. A paper feeder apparatus, comprising: a paperfeed roller that feeds a document; a separator that prevents doublefeeding of documents together with said paper feed roller; a pressingarm that presses said separator towards said paper feed roller; adocument guide provided with a pair of guide portions, the guideportions being located at both longitudinal edges of said separator, theguide portions guiding the document so that a front edge of the documentpasses over said paper feed roller, the guide portions pressing thedocument to said paper feed roller; and a spring element that providesspring force to said pressing arm and said document guide so that saidpressing arm presses said separator and said document guide presses thedocument to said paper feed roller.
 2. The paper feeder apparatusaccording to claim 1, wherein said document guide is movably mounted ata first support point spaced apart from a first pressing point at whichthe document is pressed to said paper feed roller, said pressing arm ismovably mounted at a second support point which is located between thefirst support point and a second pressing point at which said separatoris pressed, said spring element applies spring force between the firstsupport point and the first pressing point of said document guide in afirst direction and applies a spring force on a side of the secondsupport point opposite the second pressing point in a second direction.3. The paper feeder apparatus according to claim 2, wherein a positionat which said spring part applies spring force to said document guide islocated near the first support position.
 4. The paper feeder apparatusaccording to claim 1, further comprising a spring force controllingsection that controls the spring force of said spring element, saidspring force controlling section being located between said spring partand said document guide.
 5. The paper feeder apparatus accounting toclaim 1, further comprising a spring part, said spring force controllingsection being located between said spring part and said pressing arm. 6.A facsimile apparatus comprising: the paper feeder apparatus accordingto claim
 1. 7. A paper feeder apparatus, comprising: a paper feed rollerthat feeds a document; a separator that prevents double feeding ofdocuments with said paper feed roller; a pressing arm that presses saidseparator to said paper feed roller; a document guide that has a pair ofguide members, the guide members being located at both edges of saidseparator, the guide members guiding the document so that a front edgeof the document passes over said paper feed roller, the guide memberspressing the document to said paper feed roller, said document guidecomprising a one piece resin member; and a spring part that providesspring force to said pressing arm and said document guide so that saidpressing arm presses said separator and said document guide presses thedocument to said paper feed roller.